TALEN-modified T2-cell resistance to DEX in vitro and in vivo. (A) Apoptosis of T2^wt cells and T2^GR-Ex2 cells measured by annexin V and propidium iodide staining. Cells were cultured with DEX (10⁻⁴ M) for 72 hours, and the proportion of cell death was determined as positivity (right quadrants) for propidium iodide, annexin V, or both. (B) Time-response curves for cell proliferation of T2^wt (closed symbols) or T2^GR-Ex2 (open symbols) treated with DEX by using a typical 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Data are represented as means ± standard deviation from 3 independent experiments; statistical analysis was performed by 1-way ANOVA (***P < .001). (C) Splenic engraftment of T2^wt or T2^GR-Ex2 cells stained by human anti-CD45 and anti-CD4. Photographs depict the smaller size of harvested spleens from DEX-treated T2-injected recipients. A total of 5 × 106 T2^wt or T2^GR-Ex2 cells were IV injected into irradiated NSG mice treated daily with intraperitoneally injected DEX at 15 mg/kg or vehicle for 12 days. (D) Total number of human CD4⁺ cells per spleen. Data depict means from 2 independent experiments with 4 mice per group; statistical analysis was performed by 1-way ANOVA (**P < .01) with Bonferroni multiple comparisons (a nonparametric Student t test between T2 and T2 DEX groups revealed a P value of .0034). ANOVA, analysis of variance.